Chromium acetate chloride

The anhydrous hahdes, chromium (II) fluoride [10049-10-2], chromium (II) bromide [10049-25-9], CrBr2, chromium (II) chloride [10049-05-5], CrCl2, and chromium (II) iodide [13478-28-9], 03x1, are prepared by reaction of the hydrohaUde and pure Cr metal at high temperatures, or anhydrous chromium (II) acetate [15020-15-2], Cr2(CH2COO)4, atlower temperatures, or by hydrogen reduction of the Cr(III) hahde at about 500—800°C (2,12). 

A mixture of 10 mmol of the allyl bromide and 10-15 mmol of the aldehyde, dissolved in 20 mL of THF, is added dropwise at — 5 to 0°C to the chromium(II) chloride solution in THF prepared by method A or B. The mixture is stirred for 36 h at this temperature and then 15 mL of sat. sodium hydroxide and 20 g of anhyd Na2S04 are added stirring is continued for 20 min at 201C. The mixture is filtered over a pad of Celite/Na2S04 (7 l). The filtrate is concentrated and the residue purified, usually by chromatography on silica gel with pentane/diethyl ether or hexane/ethyl acetate. 

Redox titrants (mainly in acetic acid) are bromine, iodine monochloride, chlorine dioxide, iodine (for Karl Fischer reagent based on a methanolic solution of iodine and S02 with pyridine, and the alternatives, methyl-Cellosolve instead of methanol, or sodium acetate instead of pyridine (see pp. 204-205), and other oxidants, mostly compounds of metals of high valency such as potassium permanganate, chromic acid, lead(IV) or mercury(II) acetate or cerium(IV) salts reductants include sodium dithionate, pyrocatechol and oxalic acid, and compounds of metals at low valency such as iron(II) perchlorate, tin(II) chloride, vanadyl acetate, arsenic(IV) or titanium(III) chloride and chromium(II) chloride. 

Cr-ZSM-5 catalysts prepared by solid-state reaction from different chromium precursors (acetate, chloride, nitrate, sulphate and ammonium dichromate) were studied in the selective ammoxidation of ethylene to acetonitrile. Cr-ZSM-5 catalysts were characterized by chemical analysis, X-ray powder diffraction, FTIR (1500-400 cm 1), N2 physisorption (BET), 27A1 MAS NMR, UV-Visible spectroscopy, NH3-TPD and H2-TPR. For all samples, UV-Visible spectroscopy and H2-TPR results confirmed that both Cr(VI) ions and Cr(III) oxide coexist. TPD of ammonia showed that from the chromium incorporation, it results strong Lewis acid sites formation at the detriment of the initial Bronsted acid sites. The catalyst issued from chromium chloride showed higher activity and selectivity toward acetonitrile. This activity can be assigned to the nature of chromium species formed using this precursor. In general, C r6+ species seem to play a key role in the ammoxidation reaction but Cr203 oxide enhances the deep oxidation. 

Chromium(II) chloride, 4052 Cyclohexanone oxime, 2452 l,4-Dicyano-2-butene, 2311 Diethyl dicarbonate, 2444 Diethyl sulfate, Iron, Water, 1710 (Difluoroamino)difluoroacetonitrile, Hydrazine, 0630 Difluoroammonium hexafluoroarsenate, 0098 1,1-Difluorourea, 0398 Dihydroxymaleic acid, 1447 f Diketene, Acids, or Bases, or Sodium acetate, 1441 /V. /V-Dimcthylacctamidc. 1656... 

After the colour of the solution in reducer 7 has changed from green to bright light blue (1.5 to 2 hours), close clamp S, leaving clamp 10 open. Simultaneously add solutions of chromium(II) chloride and sodium acetate to vessel 22 from reducer 7 and dropping funnel 8, switching on mechanical mixer 12. 

Complexes of acetylacetone (acacH), benzoylacetone (bzacH) and dipivaloylmethane (dpmH) have been reported. The acetylacetonate [Cr(acac)2] has been prepared from chromium(II) acetate and acetylacetone.142,143 It can also be obtained by the addition of aqueous sodium acetylacetonate to an aqueous solution of chromium(II) chloride, but in any preparation the yellow solid must be filtered off and dried as rapidly as possible, otherwise the chromium(III) compound is obtained. Its magnetic moment is 4.99 BM at room temperature consistent with a high-spin d4 configuration. 142The powerful reducing ability of [Cr(acac)2] has been used to prepare iron(II) and chromium(II) complexes80 of porphyrins and related ligands. 

Trifluorochromates, ACrF3 (A = NH4, K or Rb), can be prepared in aqueous conditions from chromium(II) chloride and AF or chromium(II) acetate and AHF2.224,236 The potassium salt has also been prepared by fusing CrF2 with KF under argon.237... 

When sodium chloride is fused with anhydrous chromium(II) chloride the product is NaCrCI5 regardless of the proportions of chlorides used.222 Other cations give tetra- or tri-chloro-chromates(II) as in Sections 35.3.7.3.ii and 35.3.7.3.vi above. The solvate [pyH]3[CrBr5]-2MeC02H has been isolated from the metal acetate and pyridine in a mixture of acetyl bromide and acetic acid, and there is considerable splitting of the spin-allowed d-d band in the reflectance spectrum of this complex,255 but no detailed investigations of pentahalochromates have been reported. 

A one-liter Erlenmeyer flask is substituted in the apparatus for reduction described in Experiment No. 35. The flask is charged with 145g of chromium (III) chloride 6-hydrate dissolved in a mixture of 150ml of concentrated hydrochloric acid and an equal volume of water. Fifty-five grams of zinc (coarsely granulated or in the form of rods) is added and the reduction procedure is then followed exactly as for chromium (II) acetate. 

Chromic acid, 4223 Chromium, 4216 Chromium(II) acetate, 1489 Chromium(II) chloride, 4046 Chromium(III) chloride, 4121 Chromium(III) oxide, 4245... 

Water is prepared by taking distilled water, boiling it, and allowing it to cool in a stream of nitrogen. This water is used in the wash bottle inside the box as well as to prepare solutions of chromium (III) chloride, sodium acetate, and silver nitrate. The ether and ethanol used are distilled in a nitrogen atmosphere. 

Trivalent chromium compounds, except for acetate, nitrate, and chromium(III) chloride-hexahydrate salts, are generally insoluble in water. Some hexavalent compounds, such as chromium trioxide (or chromic acid) and the ammonium and alkali metal (e.g., sodium, potassium) salts of chromic acid are readily soluble in water. The alkaline metal (e.g., calcium, strontium) salts of chromic acid are less soluble in water. The zinc and lead salts of chromic acid are practically insoluble in cold water. Chromium(VI) compounds are reduced to chromium(III) in the presence of oxidizable organic matter. However, in natural waters where there is a low concentration of reducing materials, chromium(VI) compounds are more stable (EPA 1984a). For more information on the physical and chemical properties of chromium, see Chapter 3. 

Characteristic Chromium(O) Chromium(lll) acetate, monohydrate Chromium(lll) nitrate, nonahydrate Chromium(lll) chloride... 

When the apparatus has been flushed, a boiling solution of 16 g. (0.20 mol) of anhydrous sodium acetate dissolved in 35 ml. of water is added through E A slow nitrogen flow is maintained, and a solution of 9 g. (0.034 mol) of chromium(III) chloride 6-hydrate in 15 ml. of 0.4 N sulfuric acid is poured into the top of the redactor. The rate of flow of the chromium solution can be controlled by stopcock B. If too fast a rate is used, there is a possibility of incomplete reduction. Distilled water is poured after the chromium chloride until the effluent is only slightly colored by chromium. This requires approximately 125 ml. 

This compound is a trioxyacetophenone (OH)3C6H3COCHg, obtained by heating pyrogallol with acetic acid and zinc chloride to 150°. It may be used for printing with chromium acetate, and gives brown shades [23]. It is named Alizarin Yellow G. 

A4 -Cholestcne-3-one, 269 As-Cholestene-3-one, 380 A4-Cholestenyl acetate, 265 A9( 1 )-Cholestenylacetate, 265 Cholesteryl acetate, 51 Cholesteryl phosphorodichtoridate, 390 Cholic add, 252,416 Chromic acid, 95-96 Chromic anhydride, 96-97 Chromic anhydride in graphite, 97 Chromic anhydride-Pyridine, 96, 304 Chromium(II)-amine complexes, 97 Chromium(lll) chloride, 162 Chromium hexacarbonyl, 346 Ouomium(II) perchlorate, 97 Chromous acetate, 97-98 Chromous chloride, 506 Chromyl chloride, 98-99 Qnnamaldehyde, 97,269,406 Cinnamic alcohol, 97 Cinnamyl acetate, 322... 

In the reductive cleavage of y-lactone 17, Naito et al. [17] reported that use of calcium in liquid ammonia at -70 °C enables the production of the desired carboxylic acid 18 as the sole product in 62% yield (Scheme 4.5). Other procedures including use of aluminum amalgam, chromium(II) chloride, and zinc in acetic acid led to complete recovery of the starting y-lactone 17. 

The search is on for catalysts to replace those containing toxic heavy metals. The addition of hydrogen chloride to acetylene to form vinyl chloride is catalyzed by mercuric chloride. Rhodium (III) chloride on activated carbon works just as well and is much less toxic 97 It should be tried also in other addition reactions of acetylene as well as in trans-esteriflcation reactions of vinyl acetate. The reduction of 2 ethyl-2-hexenal to 2-ethylhexanol can be catalyzed by a mixture of copper, zinc, manganese, and aluminum oxides in 100% yield.98 This is said to be a replacement for carcinogenic copper chromite. In Reaction 4.15, the amount of toxic chromium(II) chloride has been reduced from stoichiometric to catalytic (9-15 mol% chromium(II) chloride) by the addition of manganese metal.99... 

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